I recently went from an SL4 to a CAAD10 using the same 7900 brakes and same wheels/tires. I'm running HED Belgiums with Specialized Roubaix tires that are marked as 25s, but caliper out to 26.5, I noticed that when run at 105 PSI as I always run them, the tire will rub on the spring on the inside of the caliper when my weight is properly balanced. I'm trying to figure out if perhaps the CAAD just doesn't have as much rear brake clearance, or if perhaps something is off with my caliper. Any ideas?

There is nothing wrong with your frame or the brake caliper. It is just bad luck. I can't even squeeze a 25c tire in my own frame that isn't a Cannondale.